[s-cars] Fuzz logic vs adaptive learning

[Kirby Smith]

Mihnea:

In my spare time?  :)  

Thanks for the offer.  I think such an approach would have to start with
determining what WGFV would be best to use.  There have been comments by
Scott that the OEM one is rather sluggish and has limitations in its
duty cycle bounds.  Perhaps the A'pexi valve (already installed) would
be faster/better ranging.  I don't know whether it could be adapted but
I could measure the voltage it gets when it is considerably warmer
outside.  Does the OEM WGFV see an approximately 12 Vdc signal or is it
driven from a current limiting circuit?  

I left the OEM valve connected to the ECU with caps on the ends so it
would remain clean inside.  If it is disconnected electrically, rumor
has it a code is thrown.  If the OEM WGFV is good enough, it would
certainly be more widely applicable.  I guess I wouldn't terribly mind
having the A'pexi reduced to an ultimate meter to gain Scott's peace of
mind.  ^_^

But, the Motronic approach does beg the question of first gear boost
limiting.  The Motronic would have to compare vehicle speed with rpm to
switch maps.  Or, I could just wimp out in first and never, ever get
carried away.  

kirby

engine reference data
1995 S6 (Aug 94 build date)
A'pexi boost controller set at 1.3 kg/cm^2 except 1.1 in first gear
Hoppen Stage 1 chip
stock IC 
NEA aluminum crossover pipe
Samco hoses
Dahlbeck bypass valve
stock air cleaner

trans/diff data
stock 5 sp
stock flywheel/clutch
torsen rear diff


Mihnea Cotet wrote:
> 
> Kirby,
> 
> The Motronic uses a 10x16 points boost map, as well as a 10x16 points WGFV
> duty cycle map. The boost values are "target values" and the FV duty cycles
> are set to reach the desired boost levels with a given WG spring tension.
> 
> Programming the Motronic for top feed control sounds easy enough to me as
> long as a WGFV (or sort of) is still there, it's a matter of about one hour
> of real-time tuning with my on-line emulator plugged into the ECU. Let me
> know if you feel like experimenting this spring :-))))
> 
> HTH,
> 
> Mihnea
> 
> At 16:12 25/01/2004 -0500, Kirby Smith wrote:
> >So, is the Motronic programmed with WGFV duty cycle, or with boost
> >levels to be achieved such that the Motronic continuously re-learns what
> >duty cycle to use as conditions change.
> >
> >For inversion of duty cycle to top feed, an external power transitor
> >would work.  However, if the Motronic can't learn to change duty cycle
> >to get the desired boost, then a lot of experimentation and
> >reprogramming would be needed.
> >
> >kirby
> >
> >
> >QSHIPQ at aol.com wrote:
> > >
> > > Kirby:
> > > Comments inserted
> > > In a message dated 1/24/2004 1:25:03 PM Central Standard Time,
> > > kirby.a.smith at verizon.net writes:
> > > Two points:
> > >
> > > >a) The A'pexi learns what WGFV duty cycle to use to achieve its
> > > >commanded boost pressure (gauge) vs. rpm and gear, and throttle.  When
> > > >conditions change, it has to tweak what it knows.  Overboost occurs
> > > >temporarily under colder conditions, where it is more easily tolerated.
> > > >Underboost occurs temporarily when it warms from cold conditions.
> > >
> > > I only speak to the difference between Adaptive and Fuzzy logic.  Adaptive
> > > can only plot in the known points, if you have 16 options to program in
> > each
> > > gear for instance, it can only "learn" 16 boost values (based on desires vs
> > > inputs).  Fuzzy logic is capable of much more.  You can program 16
> > 'desires', and
> > > FL cannot only learn and assign values to those 16, it can take unnassigned
> > > values between the 16 and assign a boost profile to them.
> > >
> > > >b) If we had a motronic that controlled the top of the WG, and could be
> > > >programmed by gear to make up for Audi's little embarrassing mistake in
> > > >tranny design, then I would agree with you wholeheartedly, rather than
> > > >just conceding that motronic is lower risk to the engine, but not to the
> > > >tranny unless OEM programmed.
> > >
> > > Again, not a hardware problem.  Mac 11 used a top feeder AND Mac 11/14
> > used a
> > > first gear lower boost (the wire is snipped if it's a 5spd).  I would also
> > > venture to say that no FV boost intervention in first gear is probably
> > better
> > > than *any* control.  Let the turbo ramp itself, even a k24 won't reach
> > close to
> > > a maximum boost map profile in first gear without FV assistance
> > IME.  Want a
> > > top feeder valve?  You are darn close to just inverting the values
> > assigned to
> > > a bottom feeder.  Again a software issue.
> > >
> > > Scott J
> >_______________________________________________
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